1. Field of the Invention
The present invention relates generally to computer-implemented graphics systems, and in particular, to a method, apparatus, and article of manufacture for processing constructive systems for objects in a computer-implemented graphics system.
2. Description of the Related Art
The use of Computer Assisted Drafting (CAD) application programs is well known in the art. In typical graphics programs, such as AutoCAD(trademark), there are generally two geometric grids for assisting users in constructing or placing elements. These are static regular Cartesian or Polar projection grids, based either on a world origin or a local reference origin, or in advanced systems automatically inferred from a relative object point of interest or element constructive base point. Additional assistant geometries may be provided as extensions and relationships between elements.
However, users also need assistant temporary geometries that are constructive in nature, i.e., that reflect a xe2x80x9cconstructive system.xe2x80x9d Constructive systems are important in the real world, especially for manufactured assemblies. For example, a stack of bricks is a simple 3D constructive system, wherein the stack usually includes constraints on the size of individual bricks, as well as longitudinal constraints regarding the placement and assembly of individual bricks into the stack. Alternatively, an arch comprised of bricks may be a complex 3D constructive system, wherein the arch includes constraints on the size of individual bricks, 3D placement of the bricks, attachment of the bricks, etc. The issues become even more complex when dealing with other complex assemblies of objects. Consequently, there is a need in the art for improved techniques for constructive systems in a CAD program.
To address the requirements described above, the present invention discloses a method, apparatus, and article of manufacture for using constructive systems in a computer-implemented graphics system. One or more objects stored in a database are processed to create a graphical image and the graphical image is then delivered to an output device. Each of the objects includes constructive geometric data stored therein. The constructive geometric data identifies at least one constructive system, and the constructive system identifies at least one constraint on the processing of the objects by the image engine.